Crossrail has invited tenders for the construction of the access shafts and sprayed concrete lining station tunnels at Liverpool Street and Whitechapel.
The work includes the construction of platforms, concourses, cross-passages and escalator tunnels using sprayed concrete lining techniques. It also involves the construction of temporary access shafts.
The projects will also involve the removal of excavated materials from the works by road for transfer along the Thames.
The Liverpool Street contract is set to last around 47 months. The Whitechapel contract is shorter at 37 months. Tenders are being invited for one or both lots.
The deadline for tenders or requests to participate is 15 December. The announcement follows similar calls for tenders for Tottenham Court Road and Bond Street stations and two tunnelled sections in the last two months.